Casein and Insulin Sensitivity

I was reading about the Paleolithic Diet and I came across this study ( http://www.thepaleodiet.com/articles/J%20Nutr%20Environ%20Med%202003.pdf ) from the Journal of Nutritional and Environmental Medicine that suggests avoiding dairy and in particular references a study on rats that showed casein (and soy protein) decreased insulin sensitivity.

I know that is only a study on rats, but does anyone know any more about this or if anyone has done human studies to measure the same thing? It seems like that is an area of research which would have been done already, so hopefully someone can shed some light on the topic.

hmmmm. Fat loss improves insulin sensitivity and casein helps with fat loss, so I’m stumped. Not much effort put into this. This was just an attempt to bump.

Casein contains the most allergens of any of the proteins found in dairy, which could have an effect on insulin sensitivity for those who are sensitive to this.

Does this mean we should throw out our precious (dairy-based) protein shakes?